|Rodgers, jr, John|
|Smith jr, Sammie|
Submitted to: Environmental Pollution
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/18/1999
Publication Date: 8/1/2000
Citation: Interpretive Summary: Pesticides associated with agricultural storm water runoff are potentially harmful to animals and plants living in rivers, lakes, and streams that receive the runoff. Scientists are trying to find ways in which to decrease the concentration of pesticides entering these water bodies by storm water runoff. One potential solution to this problem involves using constructed wetlands as a best management practice. The constructed wetlands would act as a buffer between the agricultural field and the adjacent river, stream, or lake. The storm water runoff would be collected in the constructed wetland. Biological and chemical processes that occur in wetlands would then decrease the concentrations of pesticides to levels that would not harm the animals and plants in the rivers, streams, and lakes; therefore, when the water leaves the constructed wetland, it does not pose a threat to the animals and plants in the rivers, streams, and lakes. This research determined what size of constructed wetland would be necessary in an agricultural field to reduce runoff concentrations of the herbicide atrazine so that it would not harm animals or plants in rivers, lakes, and streams.
Technical Abstract: Atrazine was amended into constructed wetlands (59-73 m x 14 m x 0.3 m) for the purpose of monitoring transport and fate of the pesticide to obtain information necessary to provide future design parameters for constructed wetland mitigation of agricultural runoff. Following pesticide amendment, a simulated storm and runoff event equal to three volume additions was imposed on each wetland. Targeted atrazine concentrations were 0 mg/L (unamended control), 0.073 mg/L, and 0.147 mg/L. Water, sediment, and plant samples were collected weekly for 35 d from transects longitudinally distributed throughout each wetland and were analyzed for atrazine using gas chromatography. Between 17 - 42% of measured atrazine mass was within the first 30 - 36 m of wetlands. Atrazine was below detection limits (0.00005 mg/kg) in all sediment and plant samples collected throughout the duration of this study. Aqueous half-lives ranged from 16 - 48 d. According to these data, conservative buffer travel distances of 100 - 280 m would be necessary for effective runoff mitigation.